1. Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea
2. Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
3. Department of Internal Medicine, Hallym University College of Medicine, Anyang, Korea
4. Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
5. Department of Gastroenterology, University of Ulsan College of Medicine, Korea
6. Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, Korea
7. Department of Internal Medicine, Soonchunhyang University College of Medicine, Cheonan, Korea
8. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea